1. Field of the Invention
The present invention relates generally to chucks and, more particularly, to an equalizing power chuck.
2. Description of the Related Art
Generally, power chucks are used to hold a work-piece. Typically, these power chucks are mounted on a rotatable spindle of a machine tool. Commonly, the power chuck has a body and an axially disposed actuator mounted for reciprocation therein. The power chuck also has a plurality of axially extending rocker arms with work engaging jaws spaced radially equidistantly around the actuator and mounted for rocking movement to engage and disengage the work-piece.
An improved power chuck was disclosed in U.S. Pat. No. 5,184,833, issued Feb. 9, 1993, to Kenneth Cross and Ralph J. Gonnocci and U.S. Pat. No. 5,409,242, issued Apr. 25, 1995, to Ralph J. Gonnocci. The disclosed power chucks include a body, a plurality of work engaging jaws and a plurality of swivel mountings connecting the rocker arms to the body. However, these power chucks only had three rocker arms and work engaging jaws to engage the work-piece, which move simultaneously to engage the work-piece. If the work-piece is out-of-round, one or two of the jaws may apply more clamping pressure than the remaining jaw and, thus, lacks sensitivity in clamping of a work-piece in the chuck.
Another type of chuck known as an equalizing chuck has been provided with six rocker arms and work engaging jaws to engage the work piece. Such an equalizing chuck is disclosed in U.S. Pat. No. 5,941,538, issued Aug. 24, 1999, to Ralph J. Gonnocci. The disclosed equalizing chuck includes a body, six work engaging jaws, six rocker arms, a reciprocal actuator and six wedge-shaped segments slidably secured to the actuator to move the jaws relative to each other and exert an equalized pressure on the work-piece. However, it is desired to reduce the number of parts and grip the work-piece with pairs of jaws simultaneously with more power.